Sprint Nextel will finish shutting down its narrowband iDEN network as early as June 30, 2013, the company disclosed in 2012.

The iDEN system is the infrastructure that serves Sprint's Nextel brand and its popular push-to-talk service, which dates back to before Sprint acquired Nextel in 2005. But the by-now archaic data speeds of the technology and the costs of maintaining two totally separate networks, sounded the death knell for iDEN as far back as the merger deal's announcement in 2004.

Sprint will notify Nextel customers of the coming closure beginning on June 1 and offer promotions to encourage them to move to its CDMA service. Last October, the company launched a CDMA version of push-to-talk and for several years it has offered dual-mode handsets that can use both networks. Sprint has introduced four phones with the CDMA-based Direct Connect in the past eight months. Sprint has been decommissioning iDEN base stations as part of its methodical transition to Network Vision, a flexible infrastructure intended to accommodate both the carrier's 3G CDMA technology and its emerging 4G LTE system. About one-third of the iDEN radios were scheduled to be removed by the end of 2012.

The iDEN system only offers downstream speeds below 100K bps (bits per second), a trickle compared with the multiple megabits per second available from LTE and from WiMax, Sprint's current 4G technology, which is provided by Clearwire. One major benefit to Sprint from shutting down iDEN will be the ability to reuse its 800MHz frequencies for the Sprint LTE network, which a U.S. Federal Communications Commission ruling last week made possible.

The LTE service was scheduled to launch in the middle of 2012 on another spectrum band and later expand to 800MHz. Nextel was an upstart carrier that built its service on bits of spectrum pieced together into a national network. Its success went hand in glove with that of Motorola's iDEN technology, which had a walkie-talkie-like mechanism for users to talk directly without dialing numbers or answering calls. The push-to-talk capability helped Nextel build up a large subscriber base among tradespeople and workers in the field, such as construction crews and delivery workers. But iDEN became a technological backwater as CDMA and GSM-based technologies moved forward.

When it acquired Nextel, Sprint pledged to keep iDEN alive at least until 2007, but the network survived much longer. As late as 2008, Sprint renewed its commitment to the technology. Replicating the push-to-talkexperience on CDMA proved difficult, according to some analysts. However, in 2010, Sprint announced it would phase out the old technology in 2013.